I think a few people (non airlines pilots) here are getting ETOPS confused, it was created to make flying safer for twins, enhanced maintenance practices, flight planning, enroute weather etc the reason being should a twin have an engine failure it must divert and have the fuel to do it, these rules will enhance 3-4 engine ops but you're dreaming if you think the 3-4 engine aircraft will be required to divert to the nearest suitable like a twin, they will likely continue to the furthest suitable and land with whatever company/aviation body reserves that are required for a 3-4 engine landing at destination. Just like EK and BA (without the incorrect fuel balancing procedure) they would have made the destination had they been using the Boeing fuel balance procedure.
ETOPS isn't you must divert with an engine failure, it's should you have a engine failure the aviation body has made rules that the route is safe with suitable diversion airfields within range. And they've put maintenance practices in place to make failures even more unlikely.
FCOMs/QRHs/SOPs are "Land ASAP" or "plan to land at the nearest suitable" airfield.
Twin - Engine fail - ETOPS airfield "check", QRH - Land at nearest suitable.
3-4 engine - Engine fail - ETOPS airfields "check", QRH - "checklist complete"
The whole fire suppression thing is a nice planning stage exercise as we've seen on several occasions planes on fire don't last 30 mins let alone 240!