First I wanted to provide you with a good resource of why the exclusionary rule exists and why it is necessary. That is available here
The resource here
offers a good explanation of the exceptions to the exclusionary rule that allow evidence to be admissible even when it would otherwise be excluded by the exclusionary rule.
On this, the evidence mentioned is that obtained when Officer Smith enters the house (the bills). In law there are always arguments why something is, or is not, admissible.
In this case the Officer lacked a warrant and can be said to have made an illegal entry. There was no probable cause to suspect the men were a danger to themselves or others when they were in the house nor to believe they were destroying evidence, so the officer's entry was illegal and not made due to exigent circumstances. Any evidence obtained under the illegal entry, therefore, is inadmissible.
Likewise, in this case, the prosecutor can argue two things to make the evidence admissible: (a) exigent circumstances (to prevent destruction of evidence) and (b) active pursuit (as other officers were actively, at the time Smith broke the door down, trying to get a search warrant). Active pursuit, however, is only "law" in certain states, not in all. See here
. Both of these are exceptions to the exclusionary rule.
Let me know if you have any questions.