1. Vikings 6009
2. Pedro martinez 5990
3. Nothingness 5960
4. Thad 5800
5. Czuch Chuckers 5779

Provided the last bet was in high 4000s, it would be a mistake if Vikings bet anything else but 5991 (in my opinion, of course). All of the players will bet more than 5779, that's clear. Now the second place is only 181 points above the last place so after this round, nobody should have more than 500 points, which is a proven win for the 1st place runner. If you bet lower than what Chuck has left, it's most likely you're going to fall in the pond.

If I was Chuck, I'd bet everything.
If I was Thad, I'd bet everything also.
If I was Nothingness, I'd bet 5780 hoping that Pedro would bet at least 30 points more than me.
If I was Pedro (), I'd risk it and bet 5471, trying to pass Vikings to the 1st place.
And Viking's bet is clear, 5991.