Yes. You do not need to take an important offer conversation in a setting where you cannot speak privately.

If you can answer briefly, thank them for calling and ask whether you can reconnect at a specific time later that day.

Do not feel pressured to make a decision during the call; an offer conversation is usually the start of the decision process.

When you reconnect, take notes on the key terms and ask when you will receive the written details.

I got my offer call in the middle of a meeting and asked them to call back at lunch. Totally fine.