the NKVD units in the Eastern Poland were almost exclusively jewish.
Where is the documentary evidence of this statement? You have previously mentioned that IPN have such a document which validates your statement, please, what is the title of this document, and page(s) which records 'NKVD units in the Eastern Poland were almost exclusively jewish'?
They had to escape pogroms like in Kielce for example.
And from years just before WWII with the rise of Nazi styled fascist elements in Poland:
Starting in early 1935, boycotts of Jews spread all through the Polish countryside. These were followed by pogroms: window-smashing, the overturning of Jewish market stalls, beatings, arson, and finally murder. The details of these brutalities are repetitive and terrible.
In 1935 pogroms took place at Radomsko in April, at Radosc (near Warsaw) and Grochow in May, at Grodno in May. In December  these isolated occurrences began to harden into a campaign: disturbances in Klwow, Lodz, Katowice, Kielce, and Hrubieszow were followed in January 1936 by attacks on Jews in Cracow and Warsaw, among other places.
On March 9, 1936, a pogrom occurred at Przytyk, where two Jews were killed and many houses burned: Bombs were thrown in those same months in 13 more towns, including Minsk Mazowiecki; there a second pogrom occurred in early June and, after four Jews had been killed, most of the Jewish population left for Warsaw.
During 1936 and early 1937 the pogroms became a daily occurrence in Poland, and clearly indicated increasingly better oganization. In Czestochowa riots started in June 1937 with a fight between two porters; a well-organized boycott movement against the Jews prolonged the unrest there for months. In the course of the Czestochowa pogrom, the Endek paper Ganiec Czestochowski gave lists of streets on which Jews had not as yet been robbed. 75 Jews were wounded in this particular outbreak.
In May 1937 another outbreak occurred at Brest Litovsk, where a number of Jews were killed and some 200 wounded.
Between May 1935 and January 1937, 118 Jews were killed and 1,350 wounded; 137 Jewish stores were destroyed. A total of 348 separate violent mass assaults on Jews were counted during the period, and the compilation was termed both "unofficial" and "incomplete". Another compilation showed that between the end of 1935 and March 1939, 350 Jews had been killed and 500 wounded.
The wave of pogroms did not abate throughout 1937 and 1938. In August 1937 five severe outbreaks occurred in central Poland, and anti-Jewish demonstrations occurred in seven towns, including the capital.
One result of these events was an increased movement of the Jews from smaller places, where they felt themselves exposed, to the larger towns, where they thought they would be safer.
But in early 1938 the riots spread to Warsaw, and from then on attacks on Jews in the larger cities became a normal occurrence. In 1938 and 1939 the anti-Jewish boycott movement became more and more effective. Again, it was mainly the small Jewish communities that were hit, and in this a parallel to the experience in Germany can clearly be discerned. These boycott actions were usually organized by the Endeks, but by early 1939 the government OZN group also supported them.
Question, why did the Jews turn so easily on their former friends, neighbours clients and employees ?
So simply revenge by Polish Jews
could have been a strong motivating factor to take into consideration.