You have several options at this point. When you actually "sever service" (leave a job), you need to speak with a professional who not only knows the options, but can counsel you about some of your needs in the near future.
You might wish to:
1) Borrow from your 401k.
If so, then you will want to leave the 401k alone or roll your 401k into the 401k plan of your next employer. You would not be able to "borrow" from a 401k that had been rolled into an IRA. This "borrowing" from any 401k is not highly recommended, but the option is available to you.
2) Transfer the 401k into an IRA where:
- You would have more investment options than in any 401k
- You could use various investment vehicles and strategies to bring down-side preservation to your value in volatile markets.
You should really seek counsel with a competent advisor and design a plan that fits your needs. Please do not simply call some broker and do anything without analyzing your needs and finding the best solution.