The Force transfer should not be used in this case, instead the agent should unfreeze the amount of tokens that bob has to send if this is a legitimate transaction and then Alice can call the transferFrom.
Force Transfer is a function that should never be called except in extreme cases in my opinion, that function bypasses compliance checks and freeze status, it is only to be used when there is no alternative.
If the point is that you want transfers to happen only when it has been approved by the agent (which would explain why you freeze everything and want to use force transfers) there is a way to do it in a cleaner way by using the compliance contracts to only allow transfers that are pre-approved by an agent or the issuer.
Here an example of such compliance feature T-REX/contracts/compliance/legacy/features/ApproveTransfer.sol at main · TokenySolutions/T-REX · GitHub