Remote attestation (RA) is a means of malware detection, typically realized as an interaction between a trusted verifier and a potentially compromised remote device (prover). RA is especially relevant for low-end embedded or IoT devices, incapable of protecting themselves against malware infection. Most current RA techniques require on-demand and uninterruptible (atomic) operation. The former fails to detect transient malware that enters and leaves between successive RA instances. The latter involves potentially time-consuming computation over prover's memory which can be harmful to its safety-critical functionality and general availability. However, relaxing either on-demand or atomic RA operation is tricky and prone to vulnerabilities. This paper explores issues that arise in reconciling requirements of safety-critical operation with those of secure remote attestation, including detection of migratory or transient malware. We also investigate mitigation techniques, including periodic self-measurements, and interruptible attestation modality, that involves shuffled memory traversals and various memory locking mechanisms.