You're assuming Jager would have closed off the last barrier as fast as Birech, when in fact he was tying up which led to his fall. If Jager had not fallen, Birech would have closed much faster than Jager. His 10 meter lead off the barrier would probably have been 5 (or less) by the line. 7:57 high or 7:58 low for Jager.
jag was just about out of gas, but not quite. he caught a spike, through fatigue of course, but he was able to re-accelerate so he had that little bit left to run through the tape .
verdict is second place would not have gained on him and in fact, after he gets up to speed after falling, i'm not seeing the lucky winner going much faster despite all.