Complex sentence: It has also been alleged that he only leaped through the window to avoid bullets that passed into his room, however had this been the case it is unlikely that he would not have simply lay down, rather than jumping from the window.
Split into simpler sentences: It has also been alleged that he only leaped through the window to avoid bullets that passed into his room. However had this been the case it is likely that he would have simply laid down, rather than jumping from the window.