<PAGE>   10
occurred on or before the ninetieth (90th) day after the date hereof.

         (b)     If this Agreement is terminated pursuant to Section 11(a)(i),
the Purchaser and the Sellers shall execute and deliver to the Escrow Agent the
certificate referred to in Section 2(c) of the Escrow Agreement advising the
Escrow Agent of the termination of this Agreement.  If this Agreement is
terminated as provided in Section 11(a)(ii), (iii) or (iv), then the party
terminating the Agreement shall execute and deliver to the Escrow Agent, the
certificate referred to in Section 2(c) of the Escrow Agreement and deliver a
copy thereof to the other party.  Upon termination of this Agreement pursuant
to Section 11(a), this Agreement shall forthwith become void and there shall be
no liability or obligation on the part of any party, provided, however, if
Sellers have received the proceeds from the sale of any Zapata Shares prior to
or after such termination, they shall promptly deliver the same to Purchaser.

         SECTION 12.  Voting Rights of Envirodyne Shares .  Prior to the
termination or expiration of the applicable waiting period under the HSR Act,
the Purchaser and the Sellers specifically acknowledge that the Purchaser shall
have no rights as a stockholder in the Company with respect to the Envirodyne
Shares by virtue of this Agreement or otherwise, and that all such rights shall
remain vested in the Sellers.  Subject to and effective upon, the termination
or expiration of the applicable waiting period under the HSR Act, the Sellers
hereby appoint the Purchaser with full power of substitution as their true and
lawful proxy to vote the Envirodyne Shares at any meeting, general or special,
of the stockholders of the Company in its sole discretion, and hereby appoint
the Purchaser with full power of substitution as their true and lawful
attorney-in-fact to execute one or more consents or other instruments and to
take any and all actions which the Sellers could execute or take in their
capacity as a stockholder of the Company.  The foregoing proxy and power of
attorney is coupled with an interest.

         SECTION 13.  Governing Law.  This Agreement shall be governed by and
construed in accordance with the laws of the State of New York without regard
to principles of conflicts of law.

         SECTION 14.  Counterparts and Facsimile Signatures.  This Agreement
may be signed in any number of counterparts, each of which shall be an
original, with the same effect as if the signatures thereto and hereto were
upon the same instrument.  This Agreement may be executed by facsimile
signature transmitted to any other party by electronic transmission.  The
parties shall be bound by a facsimile signature once transmitted to another





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